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ProjectEulerPython/Problems/Problem21.py

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#ProjectEuler/Python/Problem21.py
#Matthew Ellison
# Created: 03-18-19
#Modified: 07-19-20
#Evaluate the sum of all the amicable numbers under 10000
#Unless otherwise listed, all of my non-standard imports can be gotten from my pyClasses repository at https://bitbucket.org/Mattrixwv/pyClasses
"""
Copyright (C) 2020 Matthew Ellison
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
"""
from Problems.Problem import Problem
from Stopwatch import Stopwatch
from Unsolved import Unsolved
import Algorithms
class Problem21(Problem):
#Variables
__limit = 10000 #The top number that will be evaluated
#Functions
#Constructor
def __init__(self):
super().__init__("Evaluate the sum of all the amicable numbers under 10000")
self.divisorSum = [] #Holds the sum of the divisors of the subscript number
self.amicable = [] #Holds all amicable numbers
def solve(self):
#If the problem has already been solved do nothing and end the function
if(self.solved):
return
#Start the timer
self.timer.start()
#Generate the divisors of all the numbers < 10000, get their sum, and add it to the list
self.divisorSum.append(0) #Start with a 0 in the [0] location
for cnt in range(1, self.__limit):
divisors = Algorithms.getDivisors(cnt) #Get all the divisors of a number
if(len(divisors) > 1):
divisors.pop() #Remove the last entry because it will be the number itself
self.divisorSum.append(int(sum(divisors)))
#Check every sum of divisors in the list for a matching sum
for cnt in range(1, len(self.divisorSum)):
currentSum = self.divisorSum[cnt]
#If the sum is greater than the number of divisors then it is impossible to be amicable. Skip the number and continue
if(currentSum >= len(self.divisorSum)):
continue
#We know that divisorSum[cnt] == currentSum, so if divisorSum[currentSum] == cnt we found an amicable number
if(self.divisorSum[currentSum] == cnt):
#A number can't be amicable with itself
if(currentSum == cnt):
continue
#Add the number to the amicable vector
self.amicable.append(cnt)
#Stop the timer
self.timer.stop()
#Save the results
self.result += "All amicable numbers less than 10000 are"
for num in self.amicable:
self.result += str(num) + '\n'
self.result += "The sum of all of these amicable numbers is " + str(sum(self.amicable))
#Throw a flag to show the problem is solved
self.solved = True
#Reset the problem so it can be run again
def reset(self):
super().reset()
self.divisorSum.clear()
self.amicable.clear()
#Gets
#Returns a vector with all of the amicable number calculated
def getAmicable(self) -> list:
#If the problem hasn't been solved throw an exception
if(not self.solved):
raise Unsolved("You must solve the problem before you can get the amicable numbers")
return self.amicable
#Returns the sum of all of the amicable numbers
def getSum(self) -> int:
#If the problem hasn't been solved throw an exception
if(not self.solved):
raise Unsolved("You must solve the problem before you can get the sum of the amicable numbers")
return sum(self.amicable)
#Run the correct function if this script is called stand along
if __name__ == "__main__":
problem = Problem21()
print(problem.getDescription()) #Print the description of the problem
problem.solve() #Solve the problem
#Print the results
print(problem.getResult())
print("It took " + problem.getTime() + " to solve this algorithm")
""" Results:
All amicable numbers less than 10000 are
220
284
1184
1210
2620
2924
5020
5564
6232
6368
The sum of all of these amicable numbers is 31626
It took 59.496 milliseconds to run this algorithm
"""